Swiss Steak with Sour Cream

50 (6 ounce) pieces bottom round steak
1 quart vegetable oil
3 pounds diced onion
12 ounces flour
2 1/2 tablespoons paprika
6 quarts beef stock
1 teaspoon pepper
1/3 cup Worcestershire sauce
1/2 cup Parmesan cheese
4 cups sour cream

Heat the oil in a large skillet over medium high heat. Once hot, quickly brown the meat in batches, removing it to a large oven casserole.

Saut